MEMS Microparticle Sensor with Integrated Pump
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Solution Overview
Problem
Existing MEMS microparticles sensing devices require frequent cleaning and re-coating, making them inefficient for frequent sensing operations and unsuitable for on-field applications due to the need for specific instrumentation and substances for removing and applying sticking coatings.
Innovation Solution
A MEMS sensing device utilizing a piezoelectric micromachined ultrasonic transducer with a membrane that oscillates in response to microparticles, employing air pressure control through a MEMS pump to attract and remove particles without a sticking coating, allowing for efficient sensing and cleaning without the need for re-coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sticking coating is used to capture microparticles, then particle sensing capability is improved, but device complexity and maintenance requirements increase due to frequent cleaning and re-coating operations
Solution Approach 1:
The invention removes the sticking coating layer from the sensing system entirely. Instead of using a coating to capture particles, the system uses the natural adhesion of particles to the oscillating membrane surface through vacuum attraction, eliminating the need for coating application and removal operations.
Solution Approach 2:
The membrane performs dual functions: sensing particles through oscillation frequency changes and self-cleaning through vacuum attraction that naturally removes particles after sensing, eliminating the need for external cleaning operations and re-coating maintenance.
2Productivity
If frequent sensing operations are required, then monitoring efficiency is improved, but operation continuity deteriorates due to cleaning interruptions
Solution Approach 1:
The system enables continuous sensing operations without interruption by using vacuum attraction to remove particles automatically after each measurement cycle. The membrane can immediately resume sensing function without requiring cleaning downtime or re-coating periods, maintaining uninterrupted operation.
3Adaptability or versatility
If on-field applications are implemented, then deployment flexibility is improved, but operational feasibility deteriorates due to need for specific instrumentation and substances
Solution Approach 1:
The invention removes the requirement for external cleaning instrumentation, chemicals, and re-coating materials. The system uses only the integrated MEMS pump and membrane structure to perform both sensing and cleaning functions, eliminating the need for external substances and complex instrumentation during field operations.
Solution Approach 2:
The device is self-sufficient in field operations, using its own integrated pump to create vacuum cycles that automatically clean the membrane after sensing. No external cleaning agents, instruments, or re-coating materials are needed, making the system fully operational in remote field environments.
4Reliability
If a sticking coating is applied to capture particles, then particle capture efficiency is improved, but time consumption increases due to re-coating operations
Solution Approach 1:
The system eliminates the sticking coating layer entirely, using instead the vacuum-induced adhesion of particles to the membrane surface during oscillation. This removes the time-consuming steps of coating application and curing while maintaining effective particle capture through the sensing mechanism.
Solution Approach 2:
The system uses periodic vacuum cycles to attract particles to the membrane for sensing, then periodically reverses the pressure to release and remove particles automatically. This periodic action maintains particle capture efficiency without requiring permanent coatings or re-coating operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables continuous operation without the need for re-coating, improving efficiency and suitability for frequent sensing and on-field applications by using air pressure to attract and remove microparticles, thereby maintaining device performance.
Implementation Method 1
a piezoelectric element (120) configured to be actuated through electric signals for causing flexural motion of the membrane (110)
Implementation Method 2
the membrane (110) oscillates about its equilibrium position at a corresponding resonance frequency fr
Implementation Method 3
through one or more holes (168) in the membrane (110) when the air pressure inside the sensor substrate cavity (130) is reduced with respect to an environmental air pressure outside the sensor substrate cavity (130)
Implementation Method 4
when the air pressure inside the sensor substrate cavity (130) is increased with respect to the environmental air pressure outside the sensor substrate cavity (130)
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3C
AI summary
A MEMS sensing device (200, 200', 200", 200‴) for sensing microparticles in an environment external to the MEMS sensing device is provided. The MEMS sensing device comprises a semiconductor body (125) integrating a sensor and a pump (205; 205(1), 205(2); 205(1)(a), 205(1)(b), 205(2)(a), 205(2)(b)), the sensor including (100) a sensor cavity (130), a membrane (110) suspended over the sensor cavity (130), and a piezoelectric element (120) over the membrane (110) and configured to cause the membrane to oscillate, about an equilibrium position, at a corresponding resonance frequency when sensing electric signals are applied to the piezoelectric element during a first operative phase of the MEMS sensing device, the resonance frequency depending on an amount of microparticles located on the membrane, the membrane having a plurality of through holes (168) for establishing a fluid communication between the sensor cavity (130) and the environment; the pump is configured to cause air pressure in the sensor cavity (130) to be reduced with respect to the air pressure of the environment during the first operative phase, so that microparticles are caused to adhere onto the membrane (110) by a suction force through the through holes (168).